Toyota Introduces Production “Clean Power” Diesels

1 February 2005

Toyota is unveiling the first production version of its Clean Power concept shown last year (earlier post) in the form of a 2.2-liter diesel engine for the Avensis.

To be introduced at the upcoming Geneva Motor Show in March, the 2.2-liter Clean Power engine offers 130 kW (175 hp) of power and 400 Nm (295 lb-ft) of torque, while producing levels of NOx and PM emissions that are respectively around 50% and 80% below Euro-4 standards. (See chart to right. The D-4D 180 Clean Power refers to the concept car noted above.)

The principle of piezoelectricity describes the capacity of certain materials to deform upon the application of an electrical current and to return to their original state when the current is removed. In a piezoelectric fuel injection system, each injector is composed of a stack of piezoelectric ceramic elements. When an electric current is applied to the stack, the elements expand almost instantaneously, allowing the fuel coming from the common-rail into the cylinder.

This technique allows larger volumes of fuel to be injected in a shorter time than would be possible with solenoid injectors. It also results in greater fuel atomization to enable more efficient combustion across the range of the engine.

The Clean Power engine also uses Toyota’s D-CAT (Diesel Clean Advanced Technology) package as standard. The D-CAT emissions technology is already available in the Avensis model.

D-CAT consists of a number of elements, but at its heart is the DPNR (Diesel Particulate NOx Reduction system) 4-way catalyst that reduces NOx and PM simultaneously. (Schematic illustration of D-CAT components to the right.)

The DPNR catalyst relies on the engine management system to vary the air-fuel ratio in the exhaust gasses.

To achieve this, a fifth injector, known as Exhaust Port Injector (EPI), has been added and placed in the exhaust port. At the critical moment, fuel is injected into the exhaust gas flow in order to create stoichiometric conditions in the DPNR catalyst. This ‘rich spike’ allows the DPNR catalyst to reduce NOx and PM.

The EPI also performs the sulfur discharge control. When the sulfur accumulated in DPNR catalyst reaches a certain level, the EPI will increase the catalyst’s bed temperature in order to release the sulfur.

Toyota D-CAT also adopts a high-efficiency EGR (Exhaust Gas Recirculation) cooler to increase the density of the exhaust gasses being recirculated into the combustion chamber by reducing their temperature.

Along with the 2.2-liter Clean Power engine, Toyota is introducing another 2.2-liter engine in the mid-power range, offering 110 kW (148 hp) of power and 310 Nm (229 lb-ft) of torque.

Fuel consumption figures are not yet available. However, the current production Avensis using a 2.0-liter diesel with D-CAT consumes 5.8 liters per 100 km (combined), or 40.5 mpg (US), with CO2 emissions of 155 g/km.

At the introduction of the Clean Power concept last year, Toyota also indicated that it would extend the engine range down to 1.9 liters, 2.2 liters being the current top-end.

It will be interesting to see Toyota’s approach to the North American market with these Clean Power diesels. I haven’t seen any statements regarding their potential introduction here. I assume that Toyota will monitor the acceptance of diesels in the NA market and decide accordingly.

A recent article in Der Spiegel noted that the German Automobile Manufacturers Association (VDA) is disputing the claim of the D-Cat system. Der Spiegel, quoting an article from Automobilwoche, states that BMW, Mercedes, VW , and Audi are going after Toyota. According to the article, the VDA members have discovered that the D-Cat system begins to lose its effectiveness after 5000-8000 km, or about 3100-5000 miles.

Toyota counters that it is an isolated incident; when the system was introduced in 2003, a fleet of 60 cars drove over an extended period without trouble. Some of the cars had more than 300,000 km or roughly 186,000 miles without any signs of trouble.

If you will examine the websites of Toyota gas-to-diesel conversions (and bio-diesel websites), you will see that there is a *very* healthy demand for hi-mpg Toyota diesel engines. Indeed, people are paying big bucks to convert their vehicles. What I don't understand is why Toyota offers hi-mpg diesels everywhere in the world except North America.

Do they think we like paying twice the fuel cost to move our cars and trucks around??

Does anyone know when a Toyota diesel Pickup truck will be introduced in the U.S.? I am so anxious for the U.S. mindset to change from, "Bigger is better". Some of us are not that naive. We want fuel efficient diesels with more torque and high mpg. ratings. The east continues to get the lastest technologies and we (U.S.) continued to stand by and wait....... I want to see the "Smart" in the U.S. as well. How about the Audi A-2?? Sixty to 80 MPG will be nice.

I too have been wanting a full size, fuel efficient pickup. I currently have a 62, 3/4 ton Chevy but the 235ci engine in that thing is weak and inefficient. All of the US diesel trucks are HUGE. I need a medium duty, PU, with a small diesel, engine. Hopefully the Japanese will start importing them soon. When they do it will be sayonara for the US auto industry. LOL!!!

Just returned from two weeks in Italy, driving a Renault Espace carrying six people on winding country roads. Also visited Rome and Florence. I loved the six-speed diesel (I used to drive big American over-the-road rigs and so am predisposed to diesel power and multi-speed transmissions). I add my voice to the rising chorus, wondering "when, oh when?" will we see the real advanced diesel cars here in the US? Come on, Toyota, Honda, Hyundai, etc. We are waiting impatiently for you to start selling us what we need!

I am hoping that Toyota will give us a Diesel engine option for the new Tacoma, perhaps for 2006/2007. I would love a powerful fuel efficient mid-size pickup, plus I'm a huge Tacoma fan. In fact if they were to offer us a diesel option for the Tacoma, I would promptly place several non-vital organs on the market to fund a purchase!!

I can't understand why no auto company hasn't started selling clean burning diesels. Who wouldn't want a 4x4 tacoma that got 30 miles per gallon. Somebody please, market a diesel pickup(small or midsize, not the giants that american car companies offer) for the U.S. I had an Isuzu diesel in the early eighties that got 37-40 mpg Where did they go?

None of the Japanese auto makers have figured it out yet. During the 1970s, when fuel prices skyrocketed, Japan introduced small, fuel-efficient cars and trucks to the U.S. and left the American auto makers playing catch-up.
Fuel is skyrocketing again with no signs of coming down. Americans are screaming for light/medium sized cars and trucks, and nobody is listening. After spending five years asking my Toyota dealer when they'd offer a diesel Taco, I gave up and bought an 81 LUV diesel. I had been driving a 74 FJ40, and was thoroughly loyal to Toyota because of their quality, but I'm not going to wait forever for them to pull their heads out. I'm going to spend $20-30k on a pickup, I'm not going to settle for their "You can have it any color you want as long as it's red." standard option mentality.

I have driven Toyota trucks since I started driving. I love the quality of these trucks. However, if I don't see diesels here in the US soon, my buisness will be done elsewhere. I find it hard to believe that they don't have the tech to put a more fuel efficient truck in the US. I'de really like to have a Toyota truck I could run bio diesel through.

Just for the record...somewhere around the year 1986...
I worked for a company based in south Phila...This company had a fleet of small Toyota trucks. These were
typical of today's tiny pickup trucks. Most were gasoline..but 2 were 4 cylinder diesels..I drove both of them. They were the best engines I had ever had the privilege to run. Started faster than any of the gas ones...in any weather, hot or cold. Never needed to use the glow plugs! One of the trucks had almost half a million miles on it with the original engine before It was assigned to me. I left the company in 1991 and have never seen Toyota diesel trucks since.....Last I remember..those fantastic diesels got around 70 some MPG..or damn close with a fifth gear manual tranny...I REMEMBER FILLING IT UP WITH 10 GALLONS OF DIESEL...AND DRIVING IT ALL WEEK..I AVERAGED 1,100 MILES A WEEK ON MY SERVICE ROUTE.

I have a1982 toyota long bed with 208k+ miles I bought it with 93k on it.
After a7 year hiatus I started driving it again.It smokes a little when when first started but Ive been told that its old enough to smoke.Besides changing oil every 3k and lube is there anythin else that I should do? Also does anyone have any idea about value.

I'll add my vote! I drove a '99 Dodge Cummins & 5-speed manual for a couple of years, towing a 4-horse with living quarters. Fabulous engine. Don't want or need that much truck, but would buy a Tacoma with a small diesel in a heartbeat. Love diesels, Toyos and manual trans.

I have a 1985 Toyota Landcruiser...5 Speed Diesel. This unit will not stop...I have 402,000 KM and is still in very good condition.I have regular Garage visits and see my favourite Body shop every 2 years. I get about 23 to 25 MPG (Canadian) I wish Toyota would bring in Diesel Landcruisers to Canada. They would sell as many as they could produced if priced below $55,000 Canadian.Most of us would probably not need the leather etc.

Toyota diesel in the States is the way to go. Emissions appears to limit potential introduction in the States, but these models flourish only a scant 75 miles east of Florida in the Bahamas (vans, trucks, cars, etc.) As previously mentioned, Toyota, Nissan & Hyundai (sp.) are making nice 7 passenger vans (called buses by the masses) and selling them to smaller countries outside the US non-stop. Bigger is not better in my estimation. Bring on the 1.9 and 2.2 liter diesels in a Tacoma or Frontier. The acceleration my be light, but the towing and hauling capacity (torque) would more than outweigh the potential inability to go from "zero to 60 in 6 5.9 seconds." Who needs this in a truck anyway? Finally, one would see why small diesels may not be welcome in stricter emission standard states, but what about the states that have no emission standards or required certifications (Florida)? I am most certainly with you folks. If one was not so expensive to import from Central or South America, that would be the way to go. American really needs to get its head out of the sand. Unfortunately, the politicians will more than likely recommend support of offshore coastal drilling so they can continue to drive their jumbo SUVs rather than consider a more sensible alternative. Thanks for the opportunity to vent.